


half fish, thick dick

by daeities (xiuzabi)



Category: EXO (Band)
Genre: Bathtub Sex, Knotting, M/M, Merpeople, Tentacle Dick
Language: English
Status: Completed
Published: 2020-01-18
Updated: 2020-01-18
Packaged: 2021-02-27 14:47:49
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,305
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22298836
Author URL: https://archiveofourown.org/users/xiuzabi/pseuds/daeities
Summary: Straddling Baekhyun’s hips in the bathtub, completely naked, is not exactly what Jongdae thought he would be getting into when he decided to bring a merguy home.
Relationships: Byun Baekhyun/Kim Jongdae | Chen
Comments: 21
Kudos: 224





	half fish, thick dick

**Author's Note:**

> uh...i'm sorry? but also not. this was sitting in my folder, mostly done, so now...here it is.

Straddling Baekhyun’s hips in the bathtub, completely naked, is not exactly what Jongdae thought he would be getting into when he decided to bring a merguy home. There’s the kissing too, eager tongues lapping at each other and exploring warm mouths, and their hands sliding over stretches of bare skin, learning. Baekhyun is particularly curious, but also very sure with his touches, letting his long, webbed fingers tease at Jongdae’s throat, smooth and perfect, down over his chest to rub his nipples. Their anatomy from the waist up is mostly the same (san gills and Baekhyun’s eyes that reflect light), but Jongdae’s warm skin continues, where the other’s turns into dark and smooth, almost iridescent scales. 

He likes the feel of the human’s thighs parted over the scales, covered in a light dusting of hair that thins out, then gets thicker around his exposed cock. Baekhyun had been eager to touch and play with it since the moment Jongdae had stripped, but then it had been soft and smaller — now, its grown a bit, rigid with arousal. The merman touches it ( _ pets _ it, really) and watches as it twitches with the contact and Jongdae pushes his hips up for more. Baekhyun grins. “I thought it was weird that your...”

“Cock,” Jongdae supplies, lips curling up further in a smile.

“Your  _ cock _ is just exposed like this. But now...” His grin turns into a smirk, eyes thinning out as he leans in to nibble at his companion’s throat while his hand wraps around his dick and strokes slowly. It’s a little dry considering the lack of spit or lube, and the water in the tub is drained down to a few inches, but Baekhyun’s grip is loose — teasing.

Jongdae sighs softly and buries his face into Baekhyun’s hair, inhaling the scent of borrowed shampoo while the merman’s fist tightens for a moment before letting him go. He tries not to let himself whine from the loss of contact, especially when Baekhyun’s hands are sliding back to grip his ass and spread him open for a moment. “ _ Baekhyun _ ,” he breathes, listening as his companion chuckles below him. 

“You’re really so pretty, Jongdae.”

“Are you just saying that because you have your hands on my ass,” he questions with a smile.

“No! It’s because it’s true.” Baekhyun squeezes his ass cheeks, then lets go, running his fingers up the length of his back instead as a questioning look comes to his face. “I want to...”

“To?” 

“How do you say it,” he asks with a sigh. 

“Fuck me?” 

“I think so, yes.” 

“Good thing I want you to, too.”

He had the foresight to grab his lube out of his nightstand earlier when it had become pretty obvious what direction things were going in with their playful flirting. Jongdae picks it from where he had let it sit on the side of the tub and flips the cap open. “Do you want to,” he asks, seeing the curious look on Baekhyun’s face. 

Of  _ course _ he wants to. “How do I...” 

“Here.” Jongdae takes one of Baekhyun’s hands and puts a bit of the gel on it, coating a couple of the digits quickly. “I’m gonna guide you,” he promises before sitting up and gently pulling the merman’s hand between his thighs. Slowly, he feels out the rim of his hole and spreads some lube over it before pressing one of Baekhyun’s digits along the edge. “Feel that?” He gets an answering nod. “Push one finger in, slowly.” 

Baekhyun takes a deep breath and does as he’s told, allowing his finger to unhurriedly disappear into Jongdae’s heat as far as it can go, causing Jongdae to shake before relaxing a moment later in contentedness. He looks even more breathtaking like this, his eyes narrowed, brows furrowing just a little with the pleasure. Baekhyun likes the sight so much his cock begins to peek out from the slit in his scales, though he ignores it in favor of keeping his focus on Jongdae. 

The human is guiding his own finger inside soon enough, next to Baekhyun’s, stretching his hole a little wider while going deeper, causing his head to fall back and a moan to come to his lips. It hasn’t honestly been that long since he’s done this, considering the obvious attraction between them, despite where they come from. Also, the...lack of knowledge when it comes to anatomy. 

Suddenly, he wonders if they’re even all that compatible. 

Jongdae tilts his head back up and stares into Baekhyun’s eyes, eager and lust filled. His face is a bit flushed and his lips are parted invitingly, and though Jongdae could easily kiss him again, he lets his focus continue downwards. He’s used to the look of smooth, dark scales, smaller towards his waist, gradually getting larger on the way to his fins, but now there’s an obvious, vertical break a few inches beneath his stomach. Jongdae had figured that Baekhyun’s genitals must have been hidden away inside of his body — but thinking and seeing are two different things.

He can see the head of Baekhyun’s cock just starting to come out, wet with what Jongdae assumes is some kind of natural lubricant. He can’t help touching it, feeling the way it sticks between his digits and how Baekhyun trembles just so,  _ so _ sensitive. 

“Jongdae...,” he moans softly when the human slides a finger down to explore the rim of the opening, over smooth scales and nerve endings. In return, Baekhyun’s cock slips out further, his body giving in to the rising pleasure. 

His length is much, much more pointed at the end, and there’s no real discernible head, his cock so smooth and wet down to where it disappears in the opening. For about two seconds, Jongdae thinks that really, they aren’t so different, and then he watches the way Baekhyun’s cock practically wriggles and seeks out his touch of its own accord.

“Oh, that’s…”

So, maybe Baekhyun has a tentacle instead of a normal, average dick and Jongdae is in near shock watching the way it moves, curling into his fingers while the man himself pants at the sensation. He’s so sensitive to the touch, and Jongdae can’t get enough of it — as weird as it is — so he wraps his fist around the wet tentacle to stroke slowly just as a test. Baekhyun rests his head back against the rim of the tub in return, pretty lips parted as he lets out a whine of growing satisfaction. Jongdae is sure he also hears his name on those lips, and he wants more of that sound — more of him. 

Wanting to ride an actual tentacle is probably the  _ weirdest  _ thing Jongdae has experienced in his life, but he just doesn’t have it in him to feel any shame for it.

He lets go of Baekhyun’s cock and puts his focus back on stretching himself open, slipping another digit inside while the merman remains a little dazed. In a few moments, he manages to recover himself and moves his finger along with Jongdae’s in even motions.  _ Just a bit more _ ... He doesn’t vocalize the thought, but he feels Baekhyun adding a fourth digit so very carefully, causing Jongdae to let off a strained moan before he’s adjusting and riding their fingers in little thrusts of his hips. 

“Baekhyun, I’m...  _ Fuck _ me.”

Baekhyun doesn’t question his words or the lust in his eyes to be sure he’s ready. Jongdae is nearly shaking in his lap, hole clenching around their fingers, and his cock twitching in want between his thighs. The human sits up further all of a sudden and pulls their fingers free, leaving him stretched open and empty, hips tipping just so until the wet tip of Baekhyun’s cock is rubbing against his perineum. Just a bit more and he can feel Jongdae nearly sinking down on this length, but he pauses and wraps a hand around his base in an attempt to hold him steady while his other arm sits around Baekhyun’s neck, elbow on his shoulders.

He looks into the merman’s eyes for a moment as he lets in a deep breath, then finally starts to take him with a slow, controlled drop. Jongdae’s lashes flutter, casting shadows on his flushed cheeks, and his fingers play with Baekhyun’s hair, holding on just so. Baekhyun does his best to memorize the look on his face from furrowed brow to parted, gasping lips, but then their hips are pressed together and he’s so deep in Jongdae’s heat, he can’t help closing his eyes and letting out a loud groan.

“You’re so hot inside, Jongdae,” he says, breathless. Baekhyun doesn’t move his body, but his cock is eager to nudge and wriggle against the human’s walls, spreading more of his natural, sticky lubricant in the process. 

The sensation is... _ strange _ , but it definitely isn’t unpleasant having Baekhyun buried scales deep inside of him. There’s so much movement even if the two of them are still in the bath, adjusting to new sensations. Jongdae is the first to move, lifting his hips just a bit and then dropping again as Baekhyun groans with approval. 

“This isn’t…”

“Hmm?” Jongdae stills again, waiting with his hands on his companion’s chest.

“This isn’t how we tend to…” Baekhyun lifts a hand, only to make a motion. 

“... _ Oh _ . Yeah, I suppose no one can really ride you underwater.” Suddenly, his smile is sharp like a promise and he’s pulling his hands back while lifting his hips. Baekhyun’s tentacle dick doesn’t seem keen to leave the tight warmth of his hole, but Jongdae moves as quick as he can, turning around in the bath so the merman is looking at his back. “Let me show you what you’re missing.” 

With one hand on the rim of the bathtub, Jongdae uses the other to spread himself open as an invitation. Quickly, he feels that wet, squirming cock carefully working its way back into the warmth of his hole, so happy to be nestled inside, and when it is, Jongdae starts to move again in little rocks of his hips. He can practically feel Baekhyun’s heavy, aroused stare traveling over his body and his cock seems to just get even more wet, a bit of the lubricant dripping out of Jongdae’s hole as he moves. 

He picks up speed, faster, deeper, Baekhyun’s cock still squirming happily inside of him and Baekhyun himself letting off low, eager groans, speechless. Jongdae has a moment where he thinks...maybe human dicks are a bit ruined for him,  _ unexciting  _ compared to this, because it  _ feels  _ like Baekhyun’s cock fattens up further as he moves, still so wet. His own arousal is dripping pre-cum onto the merman’s iridescent scales, building and building with each thrust. He gets lost in the rhythm of his own hips, chasing that pleasure and that tightening feeling in his balls, so he hardly expects it when Baekhyun is suddenly pulling him back to lie against his chest. 

“ _ Ah— _ ”

“You’re pretty to watch, Jongdae, but…” 

His cock is shoved in deep and Jongdae reaches a hand back to grab onto soft hair because, he’s  _ definitely  _ growing thicker, stretching him open wider and, “ _ fuck _ .” How is that possible? But he’s also fucking a merman, so really, what  _ isn’t  _ possible at this point? 

He doesn’t get to dwell on it much since a webbed hand is wrapping around his wet length, stroking him off quickly and Jongdae can’t help himself when he fucks up between Baekhyun’s hand and the thick cock squirming inside of him. It’s still sliding over his walls like it’s exploring, though it stops and just works him over when Jongdae groans loudly from the pressure on his prostate. 

_ Definitely  _ ruined.

He comes just like that, squeezing down around the thickness of the tentacle, shooting lines across his stomach as he pants and clings on a little tighter. He can feel Baekhyun’s hot gasp against the shell of his ear, surprised and turned on from the sight of it. Slowly, his fingers pull away from Jongdae’s spent cock, moving to wipe some of the cum across his skin, getting a feel for it. A moment later though, Jongdae can feel the tentacle moving even more eagerly inside of him, and then… The merman underneath him stills completely except the gush of thick liquid in his stretched hole. Baekhyun makes a low moan against his ear, and Jongdae knows he’s never heard anything hotter than that — and then there’s the very...full feeling in his lower half. 

“Oh...did you…”

“Yes. You don’t mind?”

“No…” Jongdae licks his lips and adjusts just a bit, making Baekhyun moan softly into his neck in the process. “Wasn’t expecting the...uh,  _ expanding  _ though?”

“Sorry! Didn’t think to warn you,” he responds, but there’s still plenty of pleasure in his voice and his previously squirming cock has settled down to just...rest inside Jongdae. However, it hasn’t gotten any less thick in the process.

Jongdae tells himself not to worry, even though he’s literally never been more full before. “Does it...go down…?”

“Oh…” Baekhyun is perking up a little, running his hand along Jongdae’s tummy gently. “It takes a bit… If you were...uh, like me...but a woman… It helps keep everything... _ in _ .”

“Right. That’s fair.”

They go quiet for a bit, because really, what’s there to say. Jongdae still has a bit of coping to do with the fact he fucked a merguy and it was the best dick of his life — sadly putting his ex-boyfriend Chanyeol in second place overall. But then Baekhyun is speaking in the silence. 

“Is it...inappropriate to ask you to be my boyfriend right now?”

Jongdae isn’t really sure how to date a guy that’s half fish, but he thinks they can make it work.


End file.
